Body wall development in lamprey and a new perspective on the origin of vertebrate paired fins.
Body wall development in lamprey and a new perspective on the origin of vertebrate paired fins.
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七鳃鳗的体壁发育和脊椎动物成对鳍起源的新视角。
DOI：
10.1073/pnas.1304210110
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发表时间：
2013
影响因子：
11.1
通讯作者：
Burke,AnnC
中科院分区：
文献类型：
--
作者：
Tulenko,FrankJ;McCauley,DavidW;Mackenzie,EthanL;Mazan,Sylvie;Kuratani,Shigeru;Sugahara,Fumiaki;Kusakabe,Rie;Burke,AnnC
关于成对附肢进化起源的经典假设提出，前体结构（鳃弓和侧鳍褶皱）转变为成对鳍。在发育过程中，颌口成对的附肢形成为体壁体壁的生长物，体壁是一种由体细胞侧板中胚层（LPM）和覆盖的外胚层组成的组织。在羊膜动物中，LPM 为远轴肌肉组织提供结缔组织，并形成肢间体壁的腹外侧真皮。该性状的系统发育分布不确定，因为尚未在羊膜动物中进行 LPM 谱系分析。我们关注体胸的进化史，以深入了解成对鳍首次出现的组织环境。七鳃鳗在获得成对鳍之前就与其他脊椎动物有所不同，并为研究附肢前状况提供了模型。我们提出了重要的染料命运图，表明七鳃鳗中体壁被消除，因为在肌节延伸过程中，LPM 与外胚层分离并隔离到体腔内壁。我们还研究了猫鲨和蝾螈颅后中胚层的分布。与七鳃鳗相反，我们的研究结果支持 LPM 对这些类群的躯干体壁的贡献，这与已发表的羊膜动物数据相似。总的来说，这些数据使我们推测，体侧壁中持续存在的躯体肋是一种颌口突触型，而 LPM 的重新分布是产生最终产生成对鳍的新型发育模块的关键步骤。这些胚胎学标准可以将争论重新集中在成对鳍的起源上，并产生可通过对遗传重新部署的来源、序列和程度的比较研究来检验的假设。
Classical hypotheses regarding the evolutionary origin of paired appendages propose transformation of precursor structures (gill arches and lateral fin folds) into paired fins. During development, gnathostome paired appendages form as outgrowths of body wall somatopleure, a tissue composed of somatic lateral plate mesoderm (LPM) and overlying ectoderm. In amniotes, LPM contributes connective tissue to abaxial musculature and forms ventrolateral dermis of the interlimb body wall. The phylogenetic distribution of this character is uncertain because lineage analyses of LPM have not been generated in anamniotes. We focus on the evolutionary history of the somatopleure to gain insight into the tissue context in which paired fins first appeared. Lampreys diverged from other vertebrates before the acquisition of paired fins and provide a model for investigating the preappendicular condition. We present vital dye fate maps that suggest the somatopleure is eliminated in lamprey as the LPM is separated from the ectoderm and sequestered to the coelomic linings during myotome extension. We also examine the distribution of postcranial mesoderm in catshark and axolotl. In contrast to lamprey, our findings support an LPM contribution to the trunk body wall of these taxa, which is similar to published data for amniotes. Collectively, these data lead us to hypothesize that a persistent somatopleure in the lateral body wall is a gnathostome synapomorphy, and the redistribution of LPM was a key step in generating the novel developmental module that ultimately produced paired fins. These embryological criteria can refocus arguments on paired fin origins and generate hypotheses testable by comparative studies on the source, sequence, and extent of genetic redeployment.